Recently the importance of portability of a digital camera is increasing, and attempts to decrease the size and weight of a lens system, which is installed in the camera, is progressing in order to decrease the size, thickness and weight of the camera unit. For example, a zoom lens comprised of a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens group having positive refractive power which are disposed in order from an object, where a plastic aspherical lens is disposed in the first lens group, has been disclosed (e.g. see Japanese Patent Application Laid-Open No. 2005-37727).